New assembled Fe-trans-1,2-bis(4-pyridyl)ethylene-NCS(NCSe) complexes – hydrogen bonded and π–π interacted structure and grid structure enclathrating ligand

Reaction of FeSO4 · 7H2O with trans-1,2-bis(4-pyridyl)ethylene (tvp) and NaNCS in the mixed solvent of water and ethanol gave rise to the formation of different coordination polymers. One (Fe(tvp)2(NCS)2(H2O)2) is hydrogen bonded and π–π interacted structure, while the other ([Fe(tvp)2(NCS)2][0.5(tvp · 2EtOH)]) is 2D grid structure, which enclathrates tvp · 2EtOH. This enclathrated tvp · 2EtOH interacts with the two 2D grid sheets to form 3D structure. The same reaction was carried out with KNCSe instead of NaNCS (Fe(tvp)2(NCSe)2(H2O)2). 57Fe Mössbauer spectra revealed that all the present assembled complexes are in the FeII high-spin state. The dissociation behavior of enclathrated molecule and ligand was investigated by TG, and the resultant electronic state of iron atom was studied by 57Fe Mössbauer spectroscopy.